Plate heat exchanger port insert and a method for alleviating vibrations in a heat exchanger

ABSTRACT

An insert is provided in a flow path adjacent to the input and/or output port of a plate heat exchanger to shield heat transfer elements adjacent to the port from high velocity flow. By deflecting and redirecting the high velocity flow from the port, vibration induced stress to the heat transfer elements can be minimized. The insert is provided with a converging nozzle that directs the flow into a narrowed body. The outlet of the insert can be formed as an open end of the body or as a contoured opening in the side wall of the body. Flow can also be more uniformly distributed to the flow channels defined between the heat transfer elements.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of co-pending U.S. patent applicationSer. No. 11/819,592, filed on Jun. 28, 2007.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to heat exchangers that experience flow inducedvibrations. The invention, in particular, relates to plate heatexchangers and fluid flow at the inlet and outlet ports of heatexchangers.

2. Discussion of Related Art

A conventional gasketed-plate-and-frame heat exchanger is formed by apack of heat transfer plates separated by gasket seals and supportedbetween end covers that form a frame that is typically formed of astationary cover and a movable cover, which are connected together byfasteners that clamp the heat transfer plate pack between them. Thenumber and size of the heat transfer plates is selected based on thefield of intended use of the heat exchanger. The heat transfer platesare arranged in a stacked relationship with interspaces or channelsformed between adjoining plates. These interspaces are sealed from thesurrounding environment by a weld or flexible seal. One of the covers,or both, is provided with port openings to allow inflow and outflow ofheat exchanging fluids. The heat transfer plates have correspondingopenings or plate ports that form an inlet port manifold and an outletport manifold for each fluid through the plate pack.

Typically, two different fluids are designed to flow within the heatexchanger. In operation, the heat exchanging fluids flow separatelythrough the plate heat exchanger in the different channels formedbetween the heat transfer plates. Alternating channels between platescommunicate with one of the inlet and outlet port manifolds so as todefine a flow area to conduct one of the heat exchanging fluids betweenthe port manifolds. The other channels between plates communicate withthe other inlet and outlet port manifolds to define another flow area toconduct the other heat exchanging fluid. A gasket or weld that issimilar to, or part of, the gasket or weld around the remainder of theplates is provided around the alternating ports to create separatefluid-tight flow channels. The alternating heat exchanging fluid pathsalong the surface of the heat transfer plates adjacent to the channelsprovide for heat exchange between the fluids. In operation, fluid flowsthrough each inlet port on a stationary or movable end cover to thecorresponding inlet port manifold and is then distributed to thechannels between the plates where heat exchange is effected. Then, thefluid flows from the channels into the corresponding outlet portmanifold and to the outlet port on a stationary or movable end cover.

The heat exchange fluid flowing through the pack of plates canexperience relatively high velocities at the inlet and outlet ports andthe associated port manifolds. This is especially true in large plateheat exchangers, as used in refineries, for example. In these settings,the port velocities can be as high as 7.6 m/s (25 ft/sec.) This highvelocity flow has been shown to induce vibrations in the portion of theheat transfer plates that forms the port manifold, especially in thoseplates positioned adjacent to the inlet and outlet ports on thestationary or removal covers. Vibration can create stresses that lead tomaterial fatigue and failure.

Flow distributors positioned in port manifolds of heat exchangers areknown. However, known flow distributors are used to shift flow todifferent areas of the heat exchanger or to merely more uniformlydistribute flow. For example, U.S. Pat. No. 4,303,124 to Hessari isdirected to a tube that may be disposed in the inlet duct or thedischarge duct to distribute and collect flow, respectively, along thewhole length of the ducts. The tube is disposed in the duct so thatfluid may flow around the entire tube, including at the entrance andexit and through open portions in the duct. However, this design doesnot shield the plates in the pack adjacent to the inlet and outlet portswhere the maximum fluid velocity exists.

An example of shifting flow in a heat exchanger is shown in PCTApplication WO 00/70292 in which control members permit the flow mediumto be guided to different sections in the plate package. However, inthis type of arrangement, shifting the flow does not shield the platesimmediately adjacent to the repositioned flow inlet or outlet from ahigh velocity fluid flow.

There is a need for a system to minimize vibrations induced by fluidflow in a heat exchanger. Additionally, it would be desirable to find asolution to the problems related to component fatigue and failure inheat exchangers due to fluid flow, particularly in plate heatexchangers.

BRIEF SUMMARY OF THE INVENTION

Aspects of embodiments of the invention relate to providing an effectivemechanism for and method of alleviating flow induced vibration in aplate heat exchanger.

Another aspect of embodiments of the invention relates to providing acost effective solution to minimizing adverse effects of high velocityflow in an inlet port manifold and/or an outlet port manifold of a plateheat exchanger.

Aspects of embodiments of this invention are directed to an insert foruse in a flow path of a heat exchanger comprising a heat exchangerassembly including an inlet port for passage of a heat exchanging fluid,a port manifold extending from the inlet port and having a length and afirst diameter, and heat transfer elements disposed along the length ofthe port manifold and having flow channels in communication with theport manifold for passage of the heat exchanging fluid to accomplishheat exchange and an insert disposed in the port manifold of the heatexchanger assembly. The insert includes a converging nozzle, a tubularbody, and an outlet formed in the tubular body. The tubular body has asecond diameter that is less than the first diameter. Heat exchangingfluid flows between the inlet port and the port manifold via the insertthrough the converging nozzle and its outlet. A flow space is definedalong the length of the port manifold and extends between the tubularbody and the heat transfer elements.

The invention is also directed to a plate heat exchanger comprising aframe including a first cover element and a second cover element,wherein fluid inlet and outlet ports are formed in at least one of thefirst and second cover elements, a heat transfer unit mounted to theframe including a plurality of interconnected spaced heat transferelements that define port manifolds in communication with each fluidport, wherein heat exchange flow channels are defined between adjacentheat transfer elements that communicate with the port manifolds, and aninsert positioned in at least one of the port manifolds in fluidcommunication with the associated fluid port. The insert includes anozzle extending from the associated fluid port to confine fluid flowbetween the fluid port and the port manifold, a hollow body extendingfrom the nozzle, and an outlet formed in the hollow body through whichfluid flows between the insert and the port manifold. The insert forms abarrier that deflects direct fluid flow between the inlet port and theflow channels away from the heat transfer elements that are positionedadjacent to the inlet port.

The invention is further directed to an insert for use in a flow path ofa heat exchanger comprising a body including an elongated chamber havinga side wall, a first end and a second end and a hollow interior defininga fluid flow path, a converging nozzle disposed at the first end of thebody that forms a tapered guide for a fluid stream along the fluid flowpath, an outlet formed in the body through which the fluid stream flows,and means for mounting the body at a fluid port of a heat exchanger. Theoutlet is formed as at least one contoured opening in the side wall ofthe elongated chamber of the body that has a cross section that variesalong the length of the body so that a velocity of the flow through theopening varies along the length of the outlet of the insert.

The invention is additionally directed to a method of exchanging heat ina fluid in a heat exchanger having a heat transfer element with anadjacent fluid flow channel and a port connected to the fluid flowchannel via a port manifold comprising positioning an insert at the portso that the insert extends into the port manifold, providing a fluidflow between the port and the port manifold through the insert, andshielding the heat transfer element from direct impingement of the fluidflow from the port to reduce vibration induced in the heat transferelement from the fluid flow.

These and other aspects of the invention will become apparent when takenin conjunction with the detailed description and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in conjunction with the accompanyingdrawings in which:

FIG. 1 is a schematic side view in partial section of an insert disposedwithin a heat exchanger in accordance with one embodiment of theinvention;

FIG. 2 shows the fluid flow in the heat exchanger when the insert inaccordance with FIG. 1 is used;

FIG. 3 is a partial schematic side view in partial section of an insertsimilar to FIG. 1 with a modified lip design;

FIG. 4 is a front view of the insert of FIG. 3;

FIG. 5 is a schematic side view in partial section of an insert similarto FIG. 1 with a modified outlet;

FIG. 6 is a schematic side view in partial section of an insert disposedwithin a heat exchanger in accordance with another embodiment of theinvention;

FIG. 7 is a schematic side view in partial section of an insert disposedwithin a heat exchanger in accordance with a further embodiment of theinvention;

FIG. 8 is a schematic side view in partial section of an insert disposedwithin a heat exchanger in accordance with another embodiment of theinvention;

FIG. 9 is a schematic side view in partial section of an insert disposedwithin a heat exchanger in accordance with an additional embodiment ofthe invention;

FIG. 10 is a top view of the insert of FIG. 6;

FIG. 11 is a top view of an insert similar to the insert of FIG. 7 witha modified outlet;

FIG. 12 is a front perspective view of a plate heat exchanger assembly;

FIG. 13 is a schematic side view in partial section of a conventionalplate heat exchanger assembly;

FIG. 14 shows the fluid flow in the conventional plate heat exchanger ofFIG. 13; and,

FIG. 15 is a plan view of a heat exchanger plate in accordance with aconventional design.

In the drawings, like reference numerals indicate corresponding parts inthe different figures.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

This invention is directed to heat exchanger assemblies and componentsfor use with heat exchangers. As will be recognized by those of ordinaryskill in the art, the invention may be implemented in various differenttypes of heat exchanger assemblies. For purposes of simplicity, theinvention is discussed in the context of a plate heat exchanger.However, the invention is not limited to a plate heat exchanger and maybe implemented in any type of heat exchanger assembly or any assembly inwhich components are subject to vibrations induced by fluid flow withinthe assembly. The following detailed description, therefore, is intendedto be illustrative and not limited to the particular types of heatexchanger components described.

Basically, the invention is directed to an insert for use with a heatexchanger that is placed in the fluid flow path adjacent to an inlet oroutlet port to more uniformly distribute fluid flow to the flow channelswithin the heat exchanger and to prevent direct impingement of highvelocity fluid flow against elements that are subject to vibrationinduced by the fluid flow. The insert shields the susceptible componentsfrom high velocity fluid flow, in particular, to reduce vibrations thatwould be created in the components from the high velocity flow. Inaccordance with this invention, the vibrations and resulting adverseaffects, such as material fatigue and component failure, can be avoided.

The terms used herein are intended to be conventional in the sense oftheir commonly accepted meanings in the art, especially in the art ofheat exchangers and fluid flow. However, it will be recognized by thoseof ordinary skill in the art that many of these terms can be usedinterchangeably with similar terms. For example, the term port isintended to describe an opening through which fluid flows and is oftenused to describe openings in end covers and heat transfer plates or evena series of aligned openings defining a flow path. Similar terms includeflow paths, channels, or manifolds. As this disclosure is intended toexplain the invention using a common application in the field, it willbe understood that these terms are not intended to be limiting.

FIG. 12 shows an exterior view of a conventional plate heat exchanger600, in which this invention could be used. FIG. 13 shows the interiorview of the conventional plate heat exchanger 600 without the insert inaccordance with this invention. The plate heat exchanger 600 is formedwith end covers that form a frame including a stationary cover element602 and a movable cover element 604 that support a plate pack 606 ofheat transfer elements 608. The stationary cover element 602 is fastenedby bolts, for example, to the movable cover element 604 to hold theplate pack 606 between them.

For clarity, the central portion of the plate pack 606 is represented bydashed lines, but it will be understood that the plate pack 606 includesa continuous stack of heat transfer elements 608 arranged between thestationary cover element 602 and the movable cover element 604. As isknown, the heat transfer elements 608 are arranged in a stacked, spacedconfiguration with sealing gaskets 610 disposed between adjacent plates.

As seen in FIG. 12, typically the plate heat exchanger 600 has a pair ofinlet ports 612 and a pair of outlet ports 614 with one inlet port 612and one outlet port 614 each connected to a separate port manifold incommunication with a flow channel defined between alternating pairs ofadjacent plates 608. By this, one fluid flows on one side of a heattransfer element 608, while another fluid flows on the other side of theheat transfer element 608 to accomplish a heat exchange between thefluids. Typically, the inlet port 612 and the associated outlet port 614are offset and disposed diagonally with respect to each other as seen inFIG. 12 and can be appreciated from FIG. 15. In this disclosure, theinlet and outlet ports 612 and 614, respectively, are broadly designatedto include the openings in the corresponding cover elements and anyassociated structure, which in this case are spool extensions. Ofcourse, any structure forming the inlet and outlet ports into the plateheat exchanger 10 would be included, or the inlet and outlet ports canmerely be the openings in the cover elements.

FIG. 13 shows inlet port 612 formed in the stationary cover element 602so as to connect to port manifold 616 that leads to flow channels 618.The inlet port 612 has an interior diameter D_(N) that in this case isthe same as the interior diameter D_(P) of the port manifold. It is alsopossible to have different diameters. Adjacent flow channels 620 wouldbe fed by the other inlet port and associated port manifold. As notedabove, the inlet port 612 could also be simply formed as an opening inthe cover element 602 without the spool extension shown.

FIG. 15 shows a typical heat transfer element 608. Each heat transferelement 608 is a plate formed of conducting material with openings orheat transfer element ports or plate ports 622 formed therein that willdefine the port manifold 616 when the plates 608 are aligned and sealedtogether, as seen in FIGS. 12 and 13. The end of the port manifold 616is sealed with a blank or blind flange 626 secured to the movable coverelement 604. It is also possible to form the inlet and outlet ports inthe movable cover element 604 instead of, or in conjunction with, thestationary cover element 602.

In operation, as illustrated in FIG. 14, a fluid is introduced to theplate heat exchanger 600 through the inlet port 612 at a velocityV_(port) and flows into the port manifold 616. The fluid flows acrossthe entire diameter D_(P) of the port manifold 616. As will beappreciated from FIG. 14, the fluid flow directly impinges on the edges624 of the plate ports 622 in the heat transfer elements 608. Arrowsrepresent the swirls induced in the flow at the edges 624 of the flowchannels 618. As is known in the art of fluid dynamics, the flow willdissipate along the length of the port manifold 616 as the fluid flowswithin each flow channel 618 between the plates 608. However, thevelocity of the fluid flow adjacent to the plates 608 positioned nearestto the inlet port 612 will be at its highest value when entering theport manifold 616. A similar phenomenon occurs at the port manifoldleading to the outlet port 614.

In large plate heat exchangers, the velocity V_(port) can be very high.This high velocity flow stream tends to impinge directly on the edges624 of the plate ports 622 in the heat transfer elements 608 adjacent tothe inlet port 612. The inventors have discovered that heat transferelements 608 located adjacent to the inlet port 612, and also adjacentto the outlet port 614, experience high vibrations due to the fluidflow. When liquid flow rates are in excess of 4.5 m/s (15 ft/sec), platevibration is possible. Such flow induced vibration can lead to eventualfailure of the heat transfer element 608. A Root Cause Failure Analysis(RCFA) illustrates the failure owing to flow-induced vibrations. Adetailed analysis indicates that both low-cycle and high-cycle fatiguefailures occur and supports vibration root cause. FIG. 15 shows crosshatched portions at the edge of the heat transfer element port 622 wherefailure tends to occur.

As the heat transfer elements 608 are typically formed as stamped platessupplied in certain standard sizes, it would be expensive andcomplicated to change the size of the plate ports 622 to accommodate theincreased flow. Since the diameter of the plate ports 622 is essentiallyfixed, the inventors of this invention have developed a way toaccommodate the high velocity within a standard assembly.

Referring to FIG. 1, this invention proposes installing an insert at theinlet port area and/or outlet port area of a heat exchanger assembly toprevent direct impingement of the liquid flow at the edge of the plateports in the heat transfer elements adjacent to the inlet port areaand/or the outlet port area. The insert will also more efficiently anduniformly distribute the flow into the port manifold within the pack ofheat transfer elements. The insert in accordance with this inventioncauses the fluid flow to flow outwardly (or inwardly) in a narrowedplume within the port manifold, which effectively shields the edges ofthe plate ports in the heat exchanger plates nearest to the inlet portand the outlet port from the high velocity flow that causes vibrations.

The plate heat exchanger 10 shown in FIGS. 1 and 2, similar to thatshown in FIGS. 12-14, has a frame including a stationary cover element12 and a movable cover element 14 that are secured together to clamp apack 16 of heat transfer elements 18 together in a spaced relationship.The heat transfer elements 18 are secured in a stacked, spacedrelationship by sealing gaskets 20 and define flow channels 22, 24between adjacent alternating pairs of elements 18. Again, the plate pack16 is shown partially dashed for purposes of simplicity but wouldinclude elements 18 extending entirely between the cover elements 12 and14.

An inlet port 26 is formed in one of the cover elements, in this casethe stationary cover element 12. The inlet port 26 is used to broadlydesignate the inlet into the plate heat exchanger 10 from an externalsource through the cover element 12, which can include any structureassociated with the opening in the cover element 12. In the illustratedcase shown herein, the inlet port 26 includes the spool extension andthe port/opening in the cover element 12. A port manifold 28 extendsfrom the inlet port 26 through openings or plate ports in each of theheat transfer elements 18 to the other cover element, in this case themovable cover element 14. A blank flange can be provided to seal theport manifold 28 of the cover element 14 if it is open. An outlet port,similar to that seen in FIG. 12, would be arranged in the same mannerleading from a port manifold at the other end of the plate pack 16.

An insert 30 is provided at the inlet port 26 in the port manifold 28 asseen in FIG. 1. An insert can also be provided at the outlet port. Forpurposes of simplicity, the insert 30 is described herein with respectto the inlet port 26, but it should be recognized that the descriptionis applicable to an installation at the outlet port as well since theport manifold leading to the outlet port will experience the same highvelocity issues.

The insert 30 is formed as a hollow tubular member having a first endformed as a converging nozzle 32. The opening diameter of the convergingnozzle 32 is selected to be the same or close to the same diameter D_(N)as the diameter of the inlet port 26 to promote a smooth flow of fluidinto the insert 30. The converging nozzle 32 preferably has an annularmounting flange 34 that functions as a mount to connect the insert 30 tothe heat exchanger 10. As seen in FIG. 1, the mounting flange 34 issealed between the inlet port 26 spool and the stationary cover element12 by gaskets, for example. However, it is contemplated that themounting flange 34 can connect to other portions of the heat exchanger10, including the inside of the stationary cover element 12 or the firstheat transfer element 18 adjacent to the inlet port 26. It is alsopossible to form the nozzle 32 integrally with the inlet port 26, thecovers 12, 14, or one of the heat transfer elements 18.

Extending from the nozzle 32 is a hollow, tubular elongated body 36. Anoutlet 38 is formed in the body, in this case as an open end of the body36. The body 36 defines a flow path for the fluid to flow from the inletport 26 through the nozzle 32 and out of the outlet 38. Of course, ifthe insert 30 is used at an outlet port, the flow direction would bereversed. The body 36 can have a constant diameter or be tapered towardthe outlet 38. The edge of the outlet 38 can be rounded to facilitateflow as fluid flow is enhanced around smooth or curved surfaces, as isknown. As seen in FIG. 1, a rounded lip 40 surrounds the open end of theoutlet 38.

The insert 30 can be made of any rigid material. For example, the insert30 may be made of metal, including forged steel, rolled steel ortitanium. The insert 30 may also be made of fiber reinforced glass,plastic or plastic composites. The insert 30 may be made as one piece orassembled with a separate nozzle 32 and body 36. It is also contemplatedthat stiffeners can be added if the particular application requiresadded rigidity or strength. Stiffeners can be formed as elongated ribsextending from the body 36, cross bars extending across the hollowinterior of the body 36, or perforated rings extending around the body36. In any event, the stiffeners would allow fluid to flow around andthrough the insert 30 without significant impediment.

The insert 30 extends into the port manifold 28 at least to the firstheat transfer elements 18 so that flow exiting the outlet 38 does notdirectly impinge on the edges of the ports in the heat transfer elements18 that define the port manifold 28 to shield the edges from the highestvelocity flow, which can cause vibration and wear on the elements 18, asdiscussed above. The insert 30 in this embodiment has a length less thanthe length of the port manifold 28. The insert 30 length can be fromabout 5% to about 25% of the length of the port manifold 28, forexample. The outlet 38 has a diameter D_(I) that is less than thediameter D_(P) of the port manifold 28. The outlet diameter D_(I) can befrom about 50% to 90%, or more preferably from about 70% to 80% of theport manifold diameter D_(P). While each of these values can optimizeresults, it is possible to vary the values depending on the particularfluid flow and type of heat exchanger assembly used.

The configuration of the insert 30 as it extends partially into the portmanifold with a more narrow outlet causes the fluid entering the heatexchanger to form a plume with a high velocity at its center anddiminishing velocity as the flow dissipates into the port manifold anddisperses into the existing fluid in the port manifold 28 before beingchanneled into the flow channels 22 extending between the heat transferelements 18. This plume effect prevents the edges of the ports of theheat transfer elements 18 from experiencing the direct impact of highvelocity flow entering from the inlet port 26 that occurs in prior artarrangements. The heat transfer elements 18 disposed directly adjacentto the port 26 receive fluid that has exited the outlet 38 and thenflowed in the space between the insert body 36 and the initial heattransfer elements 18 to pass into the flow channel 22. FIG. 2illustrates how the fluid flowing from the port 26 is concentrated inthe central region of the port manifold 28 with the arrows pointing tothe right in the figure. The small arrows pointing to the left in thefigure show that fluid flows back toward the heat transfer elements 18disposed directly adjacent to the port 26 after being distributed intothe port manifold 28.

The insert 30 distributes fluid flow and shields the edges of the heattransfer elements 18 from damaging high velocity flow, especially inlarge plate heat exchangers used in industrial settings, such as inpetroleum or petrochemical refineries. For example, use of the insert 30in a plate exchanger can increase the central velocity of the fluid flowin the port manifold to about 1.3 normal flow velocity, which dissipatesand causes the flow velocity experienced at the edge of the ports of theheat transfer plates adjacent to the port manifold to reduce by a factorof 2. The kinetic energy level (proportional todensity×velocity×velocity) of the fluid at this location can be reducedby a factor of 4.

It will be appreciated by those of ordinary skill in the art of fluiddynamics and heat exchangers that the velocity of the fluid (assumed tobe a liquid) flow exiting the heat exchanger at the outlet port will beapproximately the same magnitude as when it entered. Thus, channelingthe exiting fluid into an insert 30 in the port manifold leading to theoutlet port will also have the same beneficial effects described aboveby shielding the edges of the heat transfer element ports from thehighest velocity flow and minimizing vibration and wear to the heattransfer elements 18. The insert in accordance with this invention canbe used at the inlet to the plate heat exchanger, at the outlet of theplate heat exchanger or at both the inlet and the outlet, depending onthe desired application and the particular system characteristics.

FIG. 3 shows a modification of the insert 50. In this case, the insert50 has a converging nozzle 52, a mounting flange 54 and body 56 similarto the insert 30 in FIG. 1. The outlet 58 has a lip 60 that extendsoutwardly on one side toward the open channels, as seen in FIG. 4,toward the heat transfer elements 18. The extended lip 60 assists inshielding the heat transfer elements 18 from the high velocity flowexiting the insert 50. The lip 60 acts as a spillway of sorts. Althoughthe lip 60 is shown extending essentially perpendicular to the body 56,it could also extend at an angle to slope outwardly from the outlet 58.

FIG. 5 shows another modification of the insert 70. In thisconfiguration, the insert 70 has a converging nozzle 72, a mountingflange 74, a body 76 and an outlet 78 that is angled. A rounded lip 80extends around the outlet 78 and could also be enlarged if desired, asin the embodiment shown in FIG. 3. Angling the outlet 78 causes theopening to be larger and causes one side of the wall that forms the body76 to be longer than the opposed side. The longer side wall alsofunctions as a spillway shielding the heat transfer elements 18 fromdirect impingement of the fluid flow.

It any of the configurations of the inserts, the outlet can be shaped toinfluence the flow pattern in accordance with fluid dynamic principles.It is also possible to form slots or perforations in the body to allowsome fluid to exit the insert before the main outlet, but still shieldthe heat exchanging elements from direct high velocity fluid flowimpingement.

The inserts shown in FIGS. 6-11 form the outlet in the side wall ratherthan as an open end. A similar shielding effect is obtained with thisarrangement along with a more uniform distribution of flow along theport manifold.

Referring to FIG. 6, an insert 100 is formed with a converging nozzle102 at a first end leading to a hollow tubular body 104. The second end106 of the insert 100, which extends the whole length of the portmanifold 28, is positioned at the movable cover element 14. The secondend 106 can be formed as a closed end or can be closed by the coverelement 14. An outlet 108 is formed in the side wall of the body 104 asa contoured opening. The outlet 108 has a variable cross section so asto distribute the flow in a uniform manner along the length of the portmanifold 28. As will be appreciated by those of ordinary skill in theart of fluid dynamics and heat exchangers, the fluid pressure variesalong the length of the port manifold due to static fluid forces imposedby the existing fluid and by dynamic forces induced by the fluid flowingout of the port manifold to the flow channels in the plate pack 16. Theopening of the outlet 108 is contoured to take into account thevariables that impact the flow and is designed to distribute the fluidin a generally uniform manner. One shape of the opening of the outlet108 is shown in FIG. 10, for example.

The opening of the outlet 108 is disposed on the side of the insert 100that is opposed to the edges of the heat transfer elements 18 leading tothe flow channels 22 so that the fluid is deflected upward, in the caseof FIG. 6, which shows the top inlet port 26, in a direction opposite tothe flow into the flow channels 22 of the plate pack 16. The fluid thusmust flow around the insert 100 and, by this, diminishes in velocity atthe point that it impacts the edges of the heat transfer elements 18.With this arrangement, flow induced vibration does not occur, nor do thedeleterious effects of the vibration.

In the configuration of the insert 100 of FIG. 6, the converging nozzle102 is disposed within the inlet port 26 with the outlet 108 openingbeginning at the first heat transfer element 18 and flow channel 22,seen at the far left in the figure. The insert 100 is mounted in theheat exchanger so as to be centrally aligned within the port manifold28. The first end of the insert 100 is mounted by a sleeve 110 disposedaround the nozzle 102 that carries a spring biased stabilizing mountformed of a contact 112 and spring 114 supported in the sleeve 110. Thecontact 112 is biased outwardly by the spring 114 to press against aheat exchanger support surface, in this case the inlet port 26 spool.This arrangement maintains the insert 100 in a central aligned positionand resists dislodgement. The second end of the insert 100 has amounting flange 116, formed as a plate that is coupled to the movablecover element 14. As seen, a blind flange 44 is used to seal the unusedport opening the movable cover element 14. The mounting flange 116 issealed between the movable cover element 14 and the blind flange 44 witha gasket, for example. Of course, it is also possible to mount thesecond end to other portions of the frame or covers.

FIG. 7 shows a modified insert 200 that is mounted directly to thecover. Insert 200 has a converging nozzle 202 at the first end, a body204, and a second end 206. The outlet 208 is formed as a contouredopening as in the configuration of FIG. 6. A mounting flange 210 extendsfrom the nozzle 202 and is sealed to the stationary cover element 12.The second end 206 is mounted to a sleeve 46 extending from the blindflange 44.

In FIG. 8, the insert 300 is formed with a separate converging nozzle.The insert 300 has a converging nozzle 302, a body 304 and second end306. The outlet 308 is a contoured opening as in the embodiment of FIG.6. A mounting flange 310 extends from the opening at the convergingnozzle 302 and is mounted to the cover element 12. The converging nozzle302 has an open end 312 that fits into the open end 314 of the body 304in a press fit manner to form a substantially fluid tight connection. Amounting flange 316 is also disposed at the second end 306 for sealingconnection to the movable cover element 14. The separate nozzle can beused in any of the inserts in accordance with this invention.

FIG. 9 shows an embodiment in which the body of the insert is tapered.The insert 400 has a converging nozzle 402, a body 404 and a second end406. An outlet 408 is formed as an opening in the side wall of the body404 as described above. The insert 400 has a mounting flange 410 forsealing connection to stationary cover element 12. The blind flange 44has a sleeve 46 for supporting the second end 406 also as describedabove. In this configuration, the body 408 is generally conical andtapers from the first end toward the second end. This shape also assistsin flow distribution as the cross section of the hollow interior chamberinfluences the velocity and volume of the fluid exiting the insert 400.

As noted above, the outlet may be formed as a contoured opening with theprecise shape depending on the desired fluid dynamics. It is alsopossible to form the outlet as a series of openings, such as elongatedslots as shown in FIG. 11. The insert 500 in this case also has aconverging nozzle 502, a body 504, and a second end 506. Outlet 508includes slotted openings that can vary in size. Perforations or othershaped openings may also be used.

The inserts shown in FIGS. 1-5 are very simple in design and thus allowlower manufacturing costs, while still being very effective atminimizing vibration and associated wear to the heat transfer elements18. While the inserts shown in FIGS. 6-11 are more complex, the mountingmechanisms used at both ends of the insert provide increased stabilityand stiffness in large installations.

As will be evident, the various mounting arrangements may be adapted forthe various different insert designs and used in any combination. Also,the mounting flanges may be secured to various portions of the coverelements 12, 14 or the plate pack 16. The illustrations are intended toshow examples of the various combinations possible in accordance withthe invention, but are not intended to be limiting.

All of these configurations allow easy installation and removal of theinserts through either cover element depending on the particular design.For example, the insert can be accessed by removing the inlet port 26spool and/or the blind flange 44. The insert is well suited by this forretrofitting into existing plate heat exchangers.

An advantage of the insert in accordance with this invention is that thefluid flow entering and exiting the heat exchanger can be modified byeffectively altering the size of the ports and port manifolds with theinsert and deflecting high velocity flow while using standard plate packassemblies. Standard sized heat transfer elements can be used with theinsert without modification to the heat exchanger plate, which would bevery expensive and inefficient for individualized installations. Theinsert can be manufactured relatively inexpensively and installed duringassembly or retrofit into existing plate heat exchangers to reduce wearand ultimate replacement of the heat transfer plates. This offers a hugecost savings in preventing throughput losses and repair and replacementcosts to plate heat exchangers, particularly large plate heat exchangersused in refineries, for example.

Various modifications can be made in our invention as described herein,and many different embodiments of the device and method can be madewhile remaining within the spirit and scope of the invention as definedin the claims without departing from such spirit and scope. It isintended that all matter contained in the accompanying specificationshall be interpreted as illustrative only and not in a limiting sense.

1. A heat exchanger, comprising: a heat exchanger assembly including aport for passage of a heat exchanging fluid, a port manifold extendingfrom the port and having a length and a port manifold diameter, and heattransfer elements disposed along the length of the port manifold andhaving flow channels in communication with the port manifold for passageof the heat exchanging fluid to accomplish heat exchange; and an insertdisposed in the port manifold of the heat exchanger assembly, the insertcomprising a converging nozzle, a tubular body extending from theconverging nozzle, and an outlet formed in the tubular body, wherein thetubular body has a tubular body internal diameter that is less than theport manifold diameter, and wherein heat exchanging fluid flows betweenthe port and the port manifold via the insert through the convergingnozzle and the outlet, wherein a flow space is defined along the lengthof the port manifold and extends between the tubular body and the heattransfer elements, wherein the outlet of the insert has a rounded lip.2. The heat exchanger of claim 1, wherein the second diameter is betweenabout 50% and 90% of the first diameter.
 3. The heat exchanger of claim1, wherein the port manifold has a first length and the insert has asecond length extending from the nozzle to the outlet, wherein thesecond length is less than the first length.
 4. The heat exchanger ofclaim 1, wherein the heat transfer elements comprise a pack of heatexchanger plates coupled together in a stacked, spaced relationship, andthe flow channels are formed between adjacent heat exchanger plates. 5.The heat exchanger of claim 4, wherein the pack of heat exchanger platesincludes at least two entrance plates disposed adjacent to the port,wherein the insert extends at least as far as the entrance plates intothe port manifold.
 6. The heat exchanger of claim 4, wherein the outletof the insert is positioned beyond the first two heat exchanger platesin the pack.
 7. The heat exchanger of claim 1, wherein the rounded lipis enlarged on a side adjacent to the flow paths to form a spillway intothe port manifold.
 8. The heat exchanger of claim 1, wherein the outletof the insert is angled such that one side of the tubular body is longerthan another side.
 9. A plate heat exchanger, comprising: a frameincluding a first cover element and a second cover element, whereinfluid ports are formed in at least one of the first cover elements andthe second cover elements; a heat transfer unit mounted to the frameincluding a plurality of interconnected spaced heat transfer elementsthat define port manifolds in communication with each fluid port,wherein heat exchange flow channels are defined between adjacent heattransfer elements that communicate with the port manifolds; and aninsert positioned in at least one of the port manifolds in fluidcommunication with the associated fluid port, wherein the insertincludes a nozzle extending from the associated fluid port to confinefluid flow between the fluid port and the port manifold, a hollow bodyextending from the nozzle, and an outlet formed in the hollow bodythrough which fluid flows between the insert and the port manifold,wherein the insert forms a barrier that deflects direct fluid flowbetween the fluid port and the flow paths away from the heat transferelements that are positioned adjacent to the fluid port.
 10. The plateheat exchanger of claim 9, wherein the outlet is an open end of thehollow body.
 11. The plate heat exchanger of claim 10, wherein the openend is angled.
 12. The plate heat exchanger of claim 10, wherein theopen end has a rounded lip.
 13. The plate heat exchanger of claim 9,wherein the outlet is an opening formed in a side wall of the hollowbody so that fluid flows into the port manifold in a direction opposedto the flow channels between the heat transfer elements.
 14. The plateheat exchanger of claim 13, wherein the contoured opening includes aseries of slots in the side wall of the chamber body of the insert. 15.The plate heat exchanger of claim 13, wherein the outlet includes aflared lip having an enlarged side that defines a spillway.
 16. Theplate heat exchanger of claim 9, further comprising a sleeve mounted tothe frame that supports an end of the hollow body opposed to the nozzle.